Subluxing fractured plantar fat pad: a case series and description of novel sonographic findings.

Plantar fat pad syndrome has received little attention in the literature. A variety of structural changes of the plantar fat pad have been described in the literature, including atrophy, contusion, and fractured fat pad. This case series presents 4 patients (5 heels) with subluxation of a fractured plantar fat pad on dynamic ultrasound. Patients with subluxing fractured fat pad typically present with heel pain and a "snapping" or "popping" sensation when weight-bearing. Other causes of heel pain were excluded, and all patients in this series had an MRI that initially did not report any findings in the fat pad. Retrospective review of the MRI showed evidence of diffuse low T1 and T2 infiltration. To the authors' knowledge, subluxation of the plantar fat pad and the respective correlation to MRI findings have not been described in the literature. Here we describe the sonographic findings of this novel condition.

Atraumatic lateral collateral ligament complex signal abnormalities by magnetic resonance imaging in patients with osteoarthrosis of the knee.

OBJECTIVES: To determine the prevalence of atraumatic lateral collateral ligament complex (LCLC) abnormalities by magnetic resonance imaging (MRI) in patients with osteoarthrosis (OA) of the knee. METHODS: Magnetic resonance imaging scans in 96 subjects (25 with OA and 71 without OA) were retrospectively reviewed for the presence and severity of LCLC signal abnormalities. Abnormalities in the MRI scans of subjects with OA were compared with those of subjects without OA using chi2 test and the Mantel-Haenszel test for trend. RESULTS: Lateral compartment OA (23 of 25) was associated with abnormalities of the LCLC in 96% (22 of 23 subjects had fibular collateral ligament abnormalities, P < 0.0001). Medial compartment OA (25 of 25) was associated with abnormalities of the LCLC in 88% (22 of 25 subjects had fibular collateral ligament abnormalities, P < 0.0001). There was a positive trend for severity of MRI abnormalities with severity of OA (P < 0.0001 to P = 0.04). CONCLUSIONS: Lateral collateral ligament complex MRI signal abnormalities are common in patients with OA, in the absence of trauma.